1. Field of the Invention
The present invention generally relates to a system and method for range and lateral position measurement of a preceding vehicle.
2. Description of Related Art
Radar and stereo camera systems for adaptive cruise control (ACC), have been already introduced into the market. Recently, radar has been applied to for pre-crash safety systems and collision avoidance. Typically, the range and lateral position measurement of a preceding vehicle is accomplished utilizing radar and/or stereo camera systems. Radar systems can provide a very accurate range. However, millimeter wave type radar systems such as 77 Ghz systems are typically quite expensive. Laser radar is low cost but has the drawback of requiring moving parts which scan the laser across a field of view. Furthermore, the laser is less effective in adverse weather conditions which may effect the reflectivity of the preceding vehicle. For example, if mud covers the reflectors of the preceding vehicle, the reflectivity of the preceding vehicle will be less which minimizes the effectiveness of the laser. Finally, radar generally is not well suited to identify the object and give an accurate lateral position.
Stereo cameras can determine the range and identity of an object. However, these systems are typically difficult to manufacture due to the accurate alignment required between the two stereo cameras and requires two image processors.
In view of the above, it can be seen that conventional ACC systems typically do not have a high cost-performance ratio even though they may perform to the desired functional requirements. Further, it is apparent that there exists a need for an improved system and method for measuring the range and lateral position of the preceding vehicle.